Method for controlling swash plate compressor and swash plate compressor

ABSTRACT

A method for controlling a swash plate compressor and a swash plate compressor capable of preventing an overload by reducing an inclination angle of the swash plate if the torque calculated using compressor information is overloaded. Disclosed is a method for controlling a swash plate compressor including: a measuring step for measuring a compressor operation information of a swash plate compressor; a torque calculating step for calculating a calculated torque value of the swash plate compressor based on the compressor operation information; an overload determining step for determining whether an overload occurred or not by comparing the calculated torque value calculated in the torque calculating step with a torque set value; and an overload preventing step for preventing an overload by reducing an inclination angle of the swash plate of the swash plate compressor if the overload determining step determines that an overload occurred.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Phase patent application of PCT/KR2021/001892 which claims the benefit of and priority of Korean Patent Application No. 10-2020-0020132, filed in the KIPO (Korean Intellectual Property Office) on Feb. 19, 2020 and Korean Patent Application No. 10-2021-0015624, filed in the KIPO (Korean Intellectual Property Office) on Feb. 3, 2021, the entire contents of which are incorporated herein by reference.

FIELD

The present disclosure relates to a method for controlling a compressor of an air-conditioner, more particularly to, a method for controlling a swash plate compressor that controls a variable-capacity swash plate-type compressor capable of controlling an output and the swash plate compressor.

DESCRIPTION OF THE RELATED ART

An air-conditioner for a vehicle includes a compressor, a condenser, an expansion valve, and an evaporator in its configuration.

The compressor compresses a refrigerant gas discharged from the evaporator into a high-temperature and high-pressure state that is easy to liquefy and delivers it to the condenser. The compressor pumps and recirculates the refrigerant to continue cooling. The condenser liquefies the high-temperature and high-pressure refrigerant gas by exchanging heat with the outside air to cool it, and the expansion valve adiabatically expands the liquid refrigerant to drop the temperature and pressure, thereby changing it to a state that is easy to evaporate in the evaporator. The evaporator absorbs or vaporizes heat by exchanging the liquid refrigerant with the outside air introduced into the room. The outside air is cooled as heat is taken away from the refrigerant and is blown into the interior of the vehicle by a blower.

Compressors are classified into reciprocating compressors and rotary compressors according to compression methods. The reciprocating compressor compresses the working fluid (refrigerant) while the part that compresses the working fluid (refrigerant) reciprocates. A rotary compressor compresses a working fluid (refrigerant) while rotating.

The reciprocating compressor includes a crank type compressor that transmits driving force of a driving source to a plurality of pistons using a crank, a swash plate type compressor that transmits driving force to a rotating shaft in which a swash plate is installed, and a wobble plate type compressor using a wobble plate.

The swash plate compressor is divided into a fixed swash plate compressor in which the capacity of the swash plate is fixed and a variable capacity swash plate compressor in which the capacity can be controlled by changing the angle of the swash plate.

In general, the variable swash plate compressor determines the capacity of the compressor by controlling the duty of an external control valve (ECV) in order to handle the heat load required by the air-conditioner.

However, the conventional variable swash plate compressor has a problem in compressor controllability as follows.

Since the conventional variable swash plate compressor controls only the duty of the capacity control valve (ECV) according to the heat load, there is a problem in that a sudden change in an inclination angle of the swash plate, hunting, and torque change occur.

In addition, since the conventional variable swash plate compressor does not have a function for detecting and protecting belt slip and compressor sticking, there is a problem in that the compressor is damaged when belt slip or compressor sticking occurs.

SUMMARY

The present disclosure is proposed to solve the above conventional problems and the purpose of the present disclosure is to provide a method for controlling a swash plate compressor and a swash plate compressor capable of preventing overload by reducing an inclination angle of the swash plate if the torque calculated using compressor information is overloaded.

Another purpose thereof is to provide a method of controlling a clutch driving or an inclination angle of the swash plate based on revolutions per minute (RPM) so as to prevent a damage of the swash plate compressor by a belt slip and a compressor sticking and a swash plate compressor.

In addition, still another purpose thereof is to determine whether the swash plate compressor is in a low refrigerant state or not, and to generate an error alarm when it is in a low refrigerant state, thereby preventing mechanical sticking of the swash plate compressor due to lack of internal lubrication in a low refrigerant state.

In order to achieve the above purposes, the method for controlling the swash plate compressor according to the first embodiment of the present disclosure includes a measuring step S110 for measuring a compressor operation information of a swash plate compressor 100, a torque calculating step S120 for calculating a calculated torque value of the swash plate compressor based on the compressor operation information measured in the measuring step S110; an overload determining step S140 for determining whether an overload occurred or not by comparing the calculated torque value calculated in the torque calculating step S120 with a torque set value; and an overload preventing step S150 for preventing an overload by reducing an inclination angle of the swash plate of the swash plate compressor 100 if the overload determining step S140 determines that an overload occurred.

The measuring step S110 may measure the compressor operation information including a stroke and an RPM (revolutions per minute). At this instance, the measuring step S110 may measure the stroke through a stroke sensor equipped in the swash plate compressor 100.

Meanwhile, the measuring step S110 may measure the compressor operation information that further includes a discharge pressure.

The measuring step S110 may include: a cycle measuring step S115 for measuring a reciprocating cycle of a piston of the swash plate compressor; a stroke calculating step S116 for calculating a stroke of the swash plate compressor 100 based on the reciprocating cycle of the piston measured in the cycle measuring step S115; and an RPM calculating step S117 for calculating an RPM of the swash plate compressor 100 based on the reciprocating cycle of the piston measured in the measuring a cycle S115.

The overload determining step S140 may determine that an overload occurred if the calculated torque value exceeds the torque set value.

The method for controlling a swash plate compressor according to the first embodiment may further include a refrigerant discharge amount adjusting step S160 for adjusting an inclination angle of a swash plate based on a temperature of air flowed through an evaporator of an air-conditioner if the overload determining step S140 determines that a load is normal.

The refrigerant discharge amount adjusting step S160 may include: an air temperature measuring step S161 for measuring a temperature of air flowed through the evaporator; an air temperature comparing step S162 for comparing an air temperature measured in the air temperature comparing step S161 with an air temperature set value; and an inclination angle adjusting step S163 for adjusting an inclination angle of a swash plate based on the comparison result of the air temperature comparing step S162.

The inclination angle adjusting step S163 may include: an inclination angle increasing step S164 for increasing an inclination angle of a swash plate if the measured air temperature value exceeds the air temperature set value in the air temperature comparing step S162; and an inclination angle decreasing step S165 for decreasing an inclination angle of a swash plate if the measured air temperature value is below the air temperature set value in the air temperature comparing step S162.

The method for controlling a swash plate compressor according to the first embodiment may further include a transmitting step S130 for transmitting a calculated torque value calculated in the torque calculating step S120 to an engine control unit. A method for controlling a swash plate compressor according to the second embodiment may include: an air temperature measuring step S161 for measuring a temperature of air flowed through an evaporator of an air-conditioner; a target stroke calculating step S166 for calculating a target stroke based on a gap between a measured air temperature and the air temperature set value; a target ECV opening amount calculating step S167 for calculating a target ECV opening amount based on a target stroke calculated in the target stroke calculating step S166; and an ECV opening amount adjusting step S168 for adjusting an actual ECV opening amount to be a target ECV opening amount.

The method for controlling a swash plate compressor according to the second embodiment may further include a stroke comparing step S169 for comparing a measured stroke with the target stroke after the ECV opening amount adjusting step S168, and the ECV opening amount calculating step S167 and the ECV target amount adjusting step S168 may be retried if the measured stroke and the target stroke do not match in the stroke comparing step S169.

The method for controlling a swash plate compressor according to the third embodiment of the present disclosure may include: a measuring step S210 for measuring an RPM (revolutions per minute) of a swash plate compressor 100; a comparing step S220 for comparing the RPM measured in the measuring step S210 with a calculated RPM; and a protecting step S240 for stopping a clutch and generating an error alarm if the measured RPM and the calculated RPM do not match in the comparing step S220. The generation of an error alarm is characterized in lighting a warning lamp, or generating a diagnostic code.

The method for controlling a swash plate compressor according to the fourth embodiment may include: a measuring step S310 for measuring an RPM of a swash plate compressor 100; a comparing step S320 for comparing an RPM measured in the measuring step S310 with a calculated RPM; and a protecting step S330 for reducing an inclination angle of a swash plate to a minimum and generating an error alarm if the measured RPM and the calculated RPM do not match in the comparing step S320. The generation of an error alarm is characterized in lighting a warning lamp and generating a diagnostic code.

A swash plate compressor according to the embodiment of the present disclosure includes: a housing having a crankcase 112, a cylinder bore 122, a suction chamber 132 and a discharge chamber 134; a rotating shaft 140 rotatably mounted on the housing; a swash plate 150 rotating inside the crankcase 112 and interworking with the rotating shaft 140; a piston 160 interworking with the swash plate 150, reciprocating inside the cylinder bore 122 and forming a compression chamber; a measurement device 170 measuring a reciprocation cycle of the piston 160; and a control device 180 performing at least one among controlling a refrigerant discharge amount, controlling a torque, preventing belt slip and preventing compressor sticking according to the above methods based on the measured value of the measurement device. The measurement device 170 may be a stroke sensor measuring a change in a magnetic field occurred by a groove formed in the piston 160 when the piston reciprocates. The swash plate compressor according to the embodiment of the present disclosure may further include: a first pressure sensor disposed in a discharge chamber 134 and measuring a discharge pressure and a second pressure sensor disposed in a suction chamber and measuring a suction pressure 132.

The method for controlling a swash plate compressor according to the fifth and the sixth embodiments of the present disclosure includes a measuring step for measuring a compressor operation information of a swash plate compressor; a low refrigerant state determining step for determining whether the swash plate compressor is in a low refrigerant state or not; and an error alarm generating step for generating an error alarm if the swash plate compressor is in a low refrigerant state.

The measuring step measures a compressor operation information including a stroke, and the low refrigerant state determining step is characterized in determining that the swash plate compressor is in a low refrigerant state if a gap between a current value of the stroke and a predetermined appropriate value of the stroke exceeds a first reference value.

The measuring step measures a compressor operation information including a stroke and a discharge pressure; and a temperature of air flowed through an evaporator of an air-conditioner, and the low refrigerant state determining step is characterized in calculating a current refrigerant amount of the swash plate compressor by using the stroke, the discharge pressure and the air temperature; and determining that the swash plate compressor is in a low refrigerant state if a gap between a predetermined normal value of the refrigerant amount and the current refrigerant amount exceeds a second reference value.

According to the present disclosure, the method for controlling a swash plate compressor and the swash plate compressor may prevent the overload of the swash plate compressor and secure the safety of the swash plate compressor by reducing an inclination angle of the swash plate when the torque calculated using the compressor information is overloaded.

In addition, the method for controlling a swash plate compressor and the swash plate compressor may secure the controllability and reliability of the swash plate compressor and improve riding comfort and fuel economy, by controlling the refrigerant discharge amount through control of an inclination angle of the swash plate and a capacity control valve when the torque is insufficient.

In addition, the method for controlling a swash plate compressor has the effect of quickly reaching the target temperature while preventing abrupt torque fluctuations, hunting and the like by directly controlling the stroke of the swash plate compressor to adjust the temperature to the target temperature.

Further, the method for controlling a swash plate compressor may protect the compressor from belt slip and compressor sticking by comparing a measured RPM of the swash plate compressor with a calculated RPM calculated using an engine speed to determine whether belt slip and compressor sticking occurred or not and controlling the clutch according to the determination result.

Moreover, the method for controlling a swash plate compressor may prevent mechanical sticking of the swash plate compressor due to lack of internal lubrication in a low refrigerant state by determining whether the swash plate compressor is in a low refrigerant state or not and generating an error alarm if a swash plate compressor is in a low refrigerant state.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing for explaining a swash plate compressor according to an embodiment of the present disclosure.

FIGS. 2 and 3 are diagrams for explaining a control device of FIG. 1 .

FIG. 4 is a flowchart for explaining a method for controlling a swash plate compressor according to the first embodiment of the present disclosure.

FIGS. 5 and 6 are flowcharts for explaining the measuring step of FIG. 4 .

FIG. 7 is a flowchart for explaining the refrigerant discharge amount controlling step of FIG. 4 .

FIG. 8 is a flowchart for explaining a method for controlling a swash plate compressor according to the second embodiment of the present disclosure.

FIG. 9 is a flowchart for explaining a method for controlling a swash plate compressor according to the third embodiment of the present disclosure.

FIG. 10 is a flowchart for explaining a method for controlling a swash plate compressor according to the fourth embodiment of the present disclosure.

FIG. 11 is a flowchart for explaining a method for controlling a swash plate compressor according to the fifth embodiment of the present disclosure.

FIG. 12 is a flowchart for explaining a method for controlling a swash plate compressor according to the sixth embodiment of the present disclosure.

DETAILED DESCRIPTION

The advantages, features and method for accomplishment of the present invention will be more apparent from referring to the following detailed embodiments described as well as the accompanying drawings. However, the present invention is not limited to the embodiment to be disclosed below and may be implemented in different and various forms. These embodiments are provided so that the present disclosure can be thorough and complete, and are provided to fully convey the scope of the present disclosure to a person skilled in the art.

Hereinafter, the most preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings in order to facilitate a person skilled in the art to easily carry out the technical idea of the present invention. In the drawings, the same reference numerals are used to designate the same or similar components throughout the drawings even if the reference numerals are presented in each different diagram. Further, in the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

Hereinafter, a swash plate compressor according to an embodiment of the present disclosure will be described with reference to the accompanying drawings. FIG. 1 is a diagram for explaining a swash plate compressor according to an embodiment of the present disclosure. FIGS. 2 and 3 are diagrams for explaining a control device of FIG. 1 .

Referring to FIG. 1 , a variable-capacity swash plate compressor 100 capable of controlling an output by controlling an inclination angle of the swash plate is taken as an example of the swash plate compressor 100 to which a method for controlling a swash plate compressor according to the embodiment of the present disclosure is applied. Here, FIG. 1 shows the swash plate compressor 100 in which the measurement device 170 is installed to easily explain the embodiment of the present disclosure, but it is not limited thereto, and a sensor capable of measuring a cycle of reciprocating motion of the piston 160 can be applied to the swash plate compressor 100, and the structure of the swash plate compressor 100 may also be changed.

In addition, the inclination angle of the swash plate 150 means an angle between the swash plate 150 and a virtual plane perpendicular to a rotating shaft 140 at a point crossing the center point of the swash plate 150. The reduction of the inclination angle of the swash plate means that the outer periphery of the swash plate 150 is disposed close to the inclined surface by reducing the angle between the virtual surface and the swash plate 150. The increase in the inclination angle of the swash plate means that the outer periphery of the swash plate 150 is disposed far from the inclined surface by increasing the angle between the virtual surface and the swash plate 150.

The swash compressor 100 includes a housing having a crankcase 112, a cylinder bore 122, a suction chamber 132 and a discharge chamber 134.

The housing includes and is composed of a front housing 110 in which a crank chamber 112 is formed, a cylinder block 120 in which a plurality of cylinder bores 122 are formed, and a rear housing 130 in which a suction chamber 132 and a discharge chamber 134 are formed.

The housing is formed by being coupled with the cylinder block 120 interposed between the front housing 110 and the rear housing 130. At this time, the housing forms the outer shape of the swash plate compressor 100.

The swash plate compressor 100 may further include the rotating shaft 140 inserted through the center of the front housing 110 and the cylinder block 120. At this time, the swash plate 150 having a shoe 155 disposed at an end in a radial direction is inserted into the rotating shaft 140.

The swash plate compressor 100 may further include a piston 160 disposed inside the cylinder bore 122 formed in the cylinder block 120.

The piston 160 has a shoe coupling portion 165 disposed in a direction in which a square housing is located. The shoe coupling portion 165 extends horizontally by a predetermined length and is coupled to the shoe 155 of the swash plate 150. The piston 160 reciprocates inside the cylinder bore 122 as the swash plate 150 rotates at a predetermined inclination angle. At this time, the piston 160 constitutes a compression chamber together with the cylinder bore 122.

The swash plate compressor 100 may further include a measurement device 170 for measuring a cycle of reciprocating motion of the piston 160. The measurement device 170 is connected to the compression chamber to measure the cycle of reciprocating motion of the piston 160.

For example, a groove for positioning is formed in the piston 160. The measurement device 170 measures a magnetic field change occurring due to a groove formed in the piston 160 when the piston 160 reciprocates in order to measure the cycle of reciprocating motion of the piston 160.

The swash plate compressor 100 may further include a control device 180 that performs at least one among controlling a refrigerant discharge amount, controlling a torque, preventing belt slip, and preventing sticking through the method for controlling a swash plate compressor to be described later.

Referring to FIG. 2 , the control device 180 includes an output control module 181 that protects the swash plate compressor 100 from an overload and controls a refrigerant discharge amount of the swash plate compressor 100 through the method for controlling a swash plate compressor (the method for controlling a swash plate compressor of the first embodiment) to be described later on.

The output control module 181 calculates a calculated torque value by using the compressor operation information of the swash plate compressor 100 including a stroke, revolutions per minute (RPM), a suction pressure, and a discharge pressure of the swash plate compressor 100. In this case, the compressor operation information of the swash plate compressor includes a stroke, an RPM, a suction pressure, and a discharge pressure.

The output control module 181 determines whether an overload occurs in the swash plate compressor 100 or not by comparing the calculated torque value and the torque set value. At this time, the output control module 181 determines that the overload occurs when the calculated torque value exceeds the torque set value. The output control module 181 determines that a load is normal when the calculated torque value is equal to or less than the torque set value.

To prevent (resolve) the overload of the swash plate compressor 100, the output control module 181 controls the inclination angle of the swash plate when it is determined that the overload occurs. The output control module 181 reduces the output of the swash plate compressor 100 by reducing the inclination angle of the swash plate, and the overload of the swash plate compressor 100 is prevented (resolved) due to the reduction in output.

The output control module 181 controls the refrigerant discharge amount by controlling the inclination angle of the swash plate when it is determined that the load is normal. The output control module 181 adjusts the refrigerant discharge amount by adjusting the inclination angle of the swash plate based on the temperature of the air flowing through the evaporator of the air-conditioner. At this time, the output control module 181 adjusts the refrigerant discharge amount by increasing or decreasing the inclination angle of the swash plate according to the gap between the measured air temperature value and the air temperature set value.

The output control module 181 may control the refrigerant discharge amount by controlling an opening amount of an external control valve (ECV) 192 based on the calculated target stroke when it is determined that the load is normal. The output control module 181 calculates the target stroke from the gap between the measured air temperature value and the air temperature set value. The output control module 181 calculates the target ECV opening amount from the calculated target stroke. The output control module 181 controls the opening amount of the ECV 192 through an ECV driving module (not illustrated). The output control module 181 adjusts the ECV opening amount until the actual ECV opening amount and the target ECV opening amount coincide.

When the swash plate compressor 100 is a clutch type, the control device 180 includes a first protection module 183 that prevents the swash plate compressor 100 from being damaged by belt slip or compressor sticking through the method for controlling a swash plate compressor (the method for controlling a swash plate compressor of the second embodiment) to be described later on.

The first protection module 183 compares the measured RPM of the swash plate compressor 100 with the calculated RPM. In this case, the first protection module 183 may calculate the calculated RPM by using the RPM and the pulley ratio of the engine. When the measured RPM and the calculated RPM match, the first protection module 183 determines that belt slip or compressor sticking has occurred, stops the clutch 194 and generates an error alarm.

Referring to FIG. 3 , when the swash plate compressor 100 is a clutchless type, the control device 180 may include the second protection module 185 that prevents damage to the swash plate compressor 100 due to belt slip or compressor sticking through the method for controlling a swash plate compressor (the method for controlling a swash plate compressor according to the third embodiment) to be described later on.

Since the clutchless type swash plate compressor 100 does not have a clutch 194, the second protection module 185 adjusts an opening amount of the ECV 192 to minimize the inclination angle of the swash plate, thereby preventing damage to the swash plate compressor 100.

The second protection module 185 compares the measured RPM of the swash plate compressor 100 with the calculated RPM. In this case, the second protection module 185 may calculate the calculated RPM using the RPM and the pulley ratio of the engine. The second protection module 185 determines that belt slip or compressor sticking has occurred when the measured RPM and the calculated RPM match, and reduces the ECV opening amount to reduce the inclination angle of the swash plate to a minimum and generates an error alarm. By doing so, the second protection module 185 minimizes (i.e., stops) the movement of the piston 160 to prevent damage to the swash plate compressor 100.

Hereinafter, the method for controlling a swash plate compressor according to the first embodiment of the present disclosure will be described with reference to the accompanying drawings. FIG. 4 is a flowchart for explaining a method for controlling a swash plate compressor according to the first embodiment of the present disclosure. FIGS. 5 and 6 are flowcharts for explaining the measuring step of FIG. 4 . FIG. 7 is a flowchart for explaining the refrigerant discharge amount controlling step of FIG. 4 .

The method for controlling a swash plate compressor according to the first embodiment of the present disclosure calculates a torque using compressor information including the stroke, the RPM, the suction pressure and the discharge pressure of the swash plate compressor 100, and when overload occurrence is determined based on the torque, the inclination angle of the swash plate is reduced to prevent an overload, and when the torque is insufficient, the refrigerant discharge amount is controlled through control of the inclination angle of the swash plate.

Here, the inclination angle of the swash plate means an angle between the swash plate 150 and a virtual plane perpendicular to the rotating shaft 140 at a point crossing the center point of the swash plate 150. The reduction of the inclination angle of the swash plate means that the outer periphery of the swash plate 150 is disposed close to the inclined surface by reducing the angle between the virtual surface and the swash plate 150. The increase in the inclination angle of the swash plate means that the outer periphery of the swash plate 150 is disposed far from the inclined surface by increasing the angle between the virtual surface and the swash plate 150.

The method for controlling a swash plate compressor according to the first embodiment of the present disclosure controls the output of the swash plate compressor 100 by varying the reciprocating motion interval (i.e., stroke) of the piston 160 through control of the inclination angle of the swash plate to vary the output of the swash plate compressor 100.

Referring to FIG. 4 , the method for controlling a swash plate compressor includes a measuring step S110, a torque calculating step S120, a transmitting step S130, an overload determining step S140, an overload preventing step S150, and a refrigerant discharge amount adjusting step S160.

In the measuring step S110, the compressor operation information of the swash plate compressor 100 is measured. In the measuring step S110, the compressor operation information including a stroke, an RPM, and a discharge pressure is measured.

Referring to FIG. 5 , the measuring step S110 may include a stroke measuring step S111 for measuring a stroke of the swash plate compressor 100, an RPM measuring step S112 for measuring an RPM of the swash plate compressor 100 and a discharge pressure measuring step S114 for measuring a discharge pressure. Here, although FIG. 5 shows that S111 to S114 are sequentially performed in order to easily explain the measuring step S110, in actual implementation, S111 to S114 may be performed at the same time.

In this case, in the stroke measuring step S111, the RPM measuring step S112 and a discharge pressure measuring step S114, the stroke, the RPM, and the discharge pressure may be measured using sensors installed in the swash plate compressor 100.

For example, in the discharge pressure measuring step S114, the discharge pressure may be measured through an APT sensor disposed on the pipe of a discharge side of the condenser. In the discharge pressure measuring step S114, the discharge pressure may be measured using a sensor disposed in the discharge chamber 134 of the swash plate compressor 100. That is, in the discharge pressure measuring step S114, the discharge pressure may be measured using the discharge pressure sensor disposed in the discharge chamber 134.

Meanwhile, the measuring step S110 may further measure the suction pressure of the swash plate compressor 100. For example, in the measuring step S110, the suction pressure may be measured using a pressure sensor disposed in the suction chamber 132 of the swash plate compressor 100. In the measuring step S110, the suction pressure may be calculated using the information of the air-conditioner.

On the other hand, referring to FIG. 6 , the measuring step S110 may include a cycle measuring step S115 for measuring a reciprocating cycle of a piston of the swash plate compressor 100, a stroke calculating step S116 for calculating a stroke of the swash plate compressor 100 based on the reciprocating cycle of the piston measured in the cycle measuring S115, an RPM calculating step S117 for calculating an RPM of the swash plate compressor 100 based on the reciprocating cycle of the piston measured in the cycle measuring step S115 and a discharge pressure measuring step S119.

Here, in the cycle measuring step S115, measuring a cycle of the reciprocating motion of the piston through the measurement device 170 shown in FIG. 1 described above is taken as an example. The discharge pressure measuring step S119 is the same as the discharge pressure measuring step S114 of FIG. 5 .

Referring back to FIG. 4 again, in the torque calculating step S120, the calculated torque value of the swash plate compressor 100 is calculated based on the compressor operation information measured in the measuring step S110. In the transmitting step S130, the calculated torque value calculated in the torque calculating step S120 is transmitted to the engine control unit 200.

In the overload determining step S140, the calculated torque value calculated in the torque calculating step S120 is compared with a torque set value to determine whether the swash plate compressor 100 is overloaded or not. At this time, in the overload determining step S140, if the calculated torque value exceeds the torque set value, it is determined that an overload occurs. In the overload determining step S140, if the calculated torque value is less than or equal to the torque set value, it is determined that the load is normal.

In the overload preventing step S150, if it is determined that the overload occurs in the overload determining step S140, the inclination angle of the swash plate of the swash plate compressor 100 is reduced to prevent the occurrence of an overload in the swash plate compressor 100. That is, in the overload preventing step S150, when the inclination angle of the swash plate is reduced, the stroke of the piston 160 is minimized. At this time, when the stroke of the piston 160 is minimized, the output is reduced, thereby eliminating the overload of the swash plate compressor 100. In the overload preventing step S150, after relieving the overload of the swash plate compressor 100 through control of the inclination angle of the swash plate, the process returns to the measuring step S110. Through this, the method for controlling a swash plate compressor may prevent an overload of the swash plate compressor and secure the safety of the swash plate compressor 100.

In the refrigerant discharge amount adjusting step S160, if it is determined that the load is normal in the overload determining step S140, the refrigerant discharge amount is adjusted by adjusting the inclination angle of the swash plate based on the temperature of the air that has flowed through the evaporator of the air-conditioner. At this time, the process returns to the measuring step S110 after adjusting the refrigerant discharge amount in the refrigerant discharge amount adjusting step S160. By doing so, the method for controlling a swash plate compressor may improve riding comfort and fuel efficiency while securing controllability and reliability of the swash plate compressor.

Referring to FIG. 7 , the refrigerant discharge amount adjusting step S160 may include the air temperature measuring step S161, the air temperature comparing step S162, and the inclination angle adjusting step S163.

In the air temperature measuring step S161, the temperature of the air flowed through the evaporator is measured.

In the air temperature comparing step S162, the air temperature value measured in the air temperature measuring step S161 is compared with the air temperature set value.

In the inclination angle adjusting step S163, the inclination angle of the swash plate is adjusted based on the comparison result of the air temperature comparing step S162. At this time, in the inclination angle adjusting step S163, the air temperature is controlled through control of the inclination angle of the swash plate and then the process returns to the air temperature comparing step S162.

To this end, the inclination angle adjusting step S163 may include an inclination angle increasing step S164 and an inclination angle decreasing step S165.

The inclination angle increasing step S164 increases the inclination angle of the swash plate when the measured air temperature value exceeds the air temperature set value in the air temperature comparing step S162. That is, when the measured air temperature value exceeds the air temperature set value, it means that the output of the swash plate compressor 100 is lower than the required output. Accordingly, in the inclination angle increasing step S164, the output of the swash plate compressor 100 is increased by increasing the inclination angle of the swash plate. In the inclination angle increasing step S164, after increasing the inclination angle of the swash plate, the process returns to the air temperature comparing step S162.

In the inclination angle decreasing step S165, when the air temperature value measured in the air temperature comparing step S162 is less than the air temperature set value, the inclination angle of the swash plate is reduced. That is, when the measured air temperature value is less than the air temperature set value, it means that the output of the swash plate compressor 100 is higher than the required output. Accordingly, in the inclination angle decreasing step S165, the output of the swash plate compressor 100 is reduced by decreasing the inclination angle of the swash plate. In the inclination angle decreasing step S165, after decreasing the inclination angle of the swash plate, the process returns to the air temperature comparing step S162.

In this case, the inclination angle increasing step S164 ends the inclination angle adjusting step S163 if the air temperature value measured in the air temperature comparing step S162 matches the air temperature set value, and the process returns to the air temperature comparing step S162.

By doing so, the method for controlling a swash plate compressor directly controls the stroke of the swash plate compressor through control of the inclination angle of the swash plate so as to adjust the temperature to be the target temperature, thereby preventing sudden torque fluctuations, hunting and the like and quickly reaching the target temperature.

Hereinafter, the method for controlling a swash plate compressor according to the second embodiment of the present disclosure will be described with reference to the accompanying drawings. FIG. 8 is a flowchart for explaining a method for controlling a swash plate compressor according to the second embodiment of the present disclosure. Here, the method for controlling a swash plate compressor according to the second embodiment of the present disclosure may be implemented dependently on the above-described inclination angle adjusting step S163.

Referring to FIG. 8 , the method for controlling a swash plate compressor according to the second embodiment of the present disclosure may include a target stroke calculating step S166, a target ECV opening amount calculating step S167, an ECV opening amount adjusting step S168, and a stroke comparing step S169.

In the target stroke calculating step S166, the target stroke is calculated from the gap between the measured air temperature and the air temperature set value.

In the target ECV opening amount calculating step S167, a target ECV opening amount is calculated from the target stroke calculated in the target stroke calculating step S166.

In the ECV opening amount adjusting step S168, the actual ECV opening amount is adjusted to be the target ECV opening amount.

In the stroke comparing step S169, the stroke measured in the measuring step S110 is compared with the target stroke. At this time, in the stroke comparing step S169, if the measured stroke and the target stroke coincide, the process returns to the air temperature comparing step S162. In the comparing an air temperature S169, if the measured stroke and the target stroke do not match, the target ECV opening amount calculating step S167 and the ECV opening amount adjusting step S168 will be retried.

As such, the method for controlling a swash plate compressor may make the swash plate compressor rapidly reach the target temperature while preventing the swash plate compressor from abrupt torque fluctuations, hunting and the like by directly controlling the stroke of the swash plate compressor to adjust the temperature to the target temperature.

Hereinafter, the method for controlling a swash plate compressor according to the third embodiment of the present disclosure will be described with reference to the accompanying drawings. FIG. 9 is a flowchart for explaining a method for controlling a swash plate compressor according to the third embodiment of the present disclosure.

The method for controlling a swash plate compressor according to the third embodiment of the present disclosure is a control method for preventing the clutch-type swash plate compressor 100 from being damaged due to belt slip, compressor sticking and the like.

Referring to FIG. 9 , the method for controlling a swash plate compressor according to the third embodiment of the present disclosure includes a measuring step S210, a comparing step S220 and a protecting step S240.

In the measuring step S210, the RPM of the swash plate compressor 100 is measured. In the measuring step S210, the measured RPM is set as the measured RPM value and a comparing step S220 is performed.

In the comparing step S220, the RPM measured in the measuring step S210 (measured RPM) is compared with the calculated value of RPM (calculated RPM). In this case, in the comparing step S220, the calculated RPM may be calculated using the RPM of the engine and the pulley ratio. In the comparing step S220, if the measured RPM and the calculated RPM match, the process returns to the measuring step S210.

When belt slip or compressor sticking occurs in the swash plate compressor 100, the measured RPM and the calculated RPM may not match. If the clutch 194 is in a driving state when belt slip or compressor sticking occurs in the swash plate compressor 100, damage to the swash plate compressor 100 and the clutch 194 may occur.

Accordingly, if the measured RPM and the calculated RPM do not match in S220 (Yes), the swash plate compressor 100 and the clutch 194 may be damaged, so the protecting step S240 is performed.

In the protecting step S240, in order to prevent damage to the swash plate compressor 100 and the clutch 194, the clutch 194 is stopped and an alarm is generated. To this end, the protecting step S240 may include a clutch stopping step S242 and an error alarm generating step S244.

In the clutch stopping step S242, the clutch 194 in the driving state is stopped to prevent damage to the swash plate compressor 100 and the clutch 194. That is, in the method for controlling a swash plate compressor, damage to the swash plate compressor 100 and the clutch 194 can be prevented by stopping the clutch 194 to separate it from the compressor to stop the driving of the swash plate compressor 100.

At the same time, in the error alarm generating step S244, an error alarm is generated to warn that the belt slip or the compressor sticking has occurred in the swash plate compressor 100. In this case, in the error alarm generating step S244, an error alarm may be generated by turning on a warning lamp. In various embodiments, in the error alarm generating step S244, an error alarm may be generated by generating a diagnostic code and transmitting it to the engine control unit. Referring to FIG. 2 , the first protection module 183 may generate a diagnostic code and transmit it to the engine control unit 200.

Referring back to FIG. 9 , the clutch 194 is in a stopped state in S230 or an error alarm is generated in S244, and then the process returns to the measuring step S210.

As such, the method for controlling a swash plate compressor compares the measured rpm value of the swash plate compressor with the calculated RPM calculated using the engine speed to determine whether belt slip or compressor sticking occurs or not, and controls the clutch according to the determination result, thereby protecting the swash plate compressor from belt slip and compressor sticking.

The method for controlling a swash plate compressor according to the fourth embodiment of the present disclosure is explained as below with reference to accompanying drawings. FIG. 10 is a flowchart for explaining a method for controlling a swash plate compressor according to the fourth embodiment of the present disclosure.

The method for controlling a swash plate compressor according to the fourth embodiment is a control method for preventing the clutchless type swash plate compressor 100 from being damaged due to belt slip, compressor sticking and the like.

Referring to FIG. 10 , the method for controlling a swash plate compressor according to the fourth embodiment of the present disclosure includes a measuring step S310, a comparing step S320 and a protecting step S330.

In the measuring step S310, the RPM of the swash plate compressor 100 is measured. In the measuring step S310, the comparing step S320 is performed after setting the measured number of RPM as the measured RPM.

In the comparing step S320, the measured value of RPM (measured RPM) measured in the measuring step S310 is compared with the calculated RPM (calculated RPM). In this case, in the comparing step S320, the calculated RPM may be calculated using the RPM and the pulley ratio of the engine. In the comparing step S320, if the measured RPM and the calculated RPM match, the process returns to the measuring step S310.

When belt slip or compressor sticking occurs in the swash plate compressor 100, the measured RPM and the calculated RPM may not match. If the piston 160 reciprocates in a state where belt slip or compressor sticking occurs in the swash plate compressor 100, damage to the swash plate compressor 100 such as damage to the piston 160 may occur.

Accordingly, if the measured RPM and the calculated RPM do not match in S320 (Yes), it is determined that belt slip or compressor sticking has occurred, and the protecting step S330 is performed.

In the protecting step S330, the stroke of the piston 160 is stopped by controlling the inclination angle of the swash plate. By doing so, the method for controlling a swash plate compressor prevents damage to the swash plate compressor 100 due to the friction between the piston 160 and the inner wall of the cylinder bore 122 of the compressor when belt slip or compressor sticking occurs.

To this end, the protecting step S330 may include an inclination angle decreasing step S332 and an error alarm generating step S334.

In the inclination angle decreasing step S332, the inclination angle of the swash plate is decreased to a minimum. In this case, in the inclination angle decreasing step S332, the ECV opening amount may be reduced in order to decrease the inclination angle of the swash plate. That is, the method for controlling a swash plate compressor minimizes (stops) the movement of the piston 160 by minimizing the inclination angle of the swash plate.

At the same time, in the error alarm generating step S334, an error alarm is generated to warn that belt slip or compressor sticking has occurred in the swash plate compressor 100. In this case, in the error alarm generating step S334, an error alarm may be generated by turning on a warning lamp. In various embodiments, in the error alarm generating step S244, an error alarm may be generated by generating a diagnostic code and transmitting it to the engine control unit. Referring to FIG. 3 , the second protection module 185 may generate a diagnostic code and transmit the diagnostic code to the engine control unit 200.

As described above, the method for controlling a swash plate compressor compares the measured RPM of the swash plate compressor with the calculated RPM calculated using an engine speed, determines whether belt slip or compressor sticking occurs or not, and controls the ECV opening amount based on the determination result, thereby protecting the swash plate compressor from belt slip and compressor sticking.

Hereinafter, the method for controlling a swash plate compressor according to the fifth and sixth embodiments of the present disclosure will be described with reference to FIGS. 11 to 12 . The fifth and sixth embodiments are characterized in that whether the swash plate compressor is in a low refrigerant state or not is determined, and an error alarm is generated when it is determined that the swash plate compressor is in a low refrigerant state, thereby preventing the mechanical sticking of the swash plate compressor due to lack of internal lubrication in the low refrigerant state.

The fifth embodiment determines whether the swash plate compressor is in a low refrigerant state or not based on the stroke information of the swash plate compressor.

The fifth embodiment will be described with reference to FIG. 11 . The method for controlling a swash plate compressor according to the fifth embodiment includes a measuring step S410 for measuring a compressor operation information of the swash plate compressor; a low refrigerant detection condition determining step S420 for determining a detection condition of a low refrigerant; a low refrigerant state determining step S430 for determining whether the swash plate compressor is in a low refrigerant state or not; and an error alarm generating step S450 for generating an error alarm when the swash plate compressor is in a low refrigerant state.

The measuring step S410 for measuring a compressor operation information of the swash plate compressor measures the compressor operation information including the stroke. With regard to the measurement of the stroke of the compressor, the stroke may be measured through a stroke sensor provided in the swash plate compressor. In addition, the reciprocating motion of the piston of the swash plate compressor may be measured, and the stroke of the swash plate compressor may be calculated based on the measured reciprocating cycle of the piston.

In the step S420 for determining a low refrigerant detection condition, the condition to detect a low refrigerant refers to a time when the performance of the air-conditioner is at its maximum in a state when the vehicle does not move. For example, the low refrigerant detection condition refers to a time when the performance of the air conditioner is at its maximum in an idle state when the starting of the car is turned on and the car does not move. When the low refrigerant detection condition of the swash plate compressor determines that the swash plate compressor is under the low refrigerant state, the accuracy of determining whether the swash plate compressor is in a low refrigerant state or not can be further improved.

In the low refrigerant state determining step S430, when the gap between the current value of the stroke and the predetermined appropriate value of the stroke exceeds the first reference value α, the swash plate compressor is determined to be in the low-refrigerant state. In the case of a low refrigerant state, the superheat degree and subcooling of the refrigerant is changed, and the state of the suction refrigerant of the compressor is changed. In the case of being in a low refrigerant state, the compressor stroke is controlled differently from the case having a normal refrigerant amount. Therefore, the low refrigerant state of the compressor can be diagnosed by using the gap in the stroke values. Considering the accuracy of the sensor that measures the stroke, if the gap between the current stroke and the appropriate stroke value is equal to, or above 15%, it is preferable to determine that the compressor is in a low refrigerant state.

Generation of an error alarm in the error alarm generating step S450 is characterized in that a warning lamp is turned on or a diagnostic code is generated.

The sixth embodiment determines whether the swash plate compressor is in a low refrigerant state or not by calculating an amount of the refrigerant in the swash plate compressor.

Referring to FIG. 12 , a sixth embodiment will be described. The method for controlling a swash plate compressor according to the sixth embodiment includes a measuring step S510 for measuring a compressor operation information of the swash plate compressor; a low refrigerant detection condition determining step S520; a low refrigerant state determining step S530, S540 for determining whether the swash plate compressor is in a low refrigerant state or not; and an error alarm generating step S550 for generating an error alarm when the swash plate compressor is in a low refrigerant state.

In the measuring step S510 for measuring the compressor operation information of the swash plate compressor, the compressor operation information including the stroke, the discharge pressure and the temperature of the air flowing through the evaporator of the air-conditioner is measured.

The low refrigerant detection condition determining step S520 is the same as that of the fifth embodiment of FIG. 11 and thus its description is omitted.

In the low refrigerant state determining step for determining whether the swash plate compressor is in a low refrigerant state or not S530, S540, the current amount of the refrigerant of the swash plate compressor is calculated using the stroke, the discharge pressure, and the air temperature S530 and when the gap between the predetermined normal value of the refrigerant and the current amount of the refrigerant exceeds the second reference value β, it is determined that the swash plate compressor is in a low refrigerant state S540.

The current refrigerant amount calculating step S530 of the swash plate compressor may be performed by calculating the current refrigerant amount using the stroke, the discharge pressure and the air temperature. Specifically, if creating a regression equation using the stroke, the discharge pressure and the air temperature, an arithmetic expression for predicting the amount of the refrigerant in a system of a HVAC can be created. In various embodiments, the current refrigerant amount can be calculated using a regression equation by additionally including a fan voltage of the condenser, a blower voltage of the evaporator and a temperature of the outside air blown into the vehicle interior.

The generation of an error alarm in the error alarm generating step S450 is characterized in that a warning lamp is turned on or a diagnostic code is generated.

Although the exemplary embodiments according to the present disclosure have been described above, the exemplary embodiments can be modified in various forms, and it is understood that those skilled in the art can make various modifications thereof without departing from the scope of the claims of the present disclosure. 

1. A method for controlling a swash plate compressor, comprising: a measuring step for measuring compressor operation information of a swash plate compressor; a torque calculating step for calculating a calculated torque value of the swash plate compressor based on the compressor operation information measured in the measuring step; an overload determining step for determining whether an overload occurred or not by comparing the calculated torque value calculated in the torque calculating step with a torque set value; and an overload preventing step for preventing an overload by reducing an inclination angle of the swash plate of the swash plate compressor if the overload determining step determines that an overload occurred.
 2. The method for controlling the swash plate compressor of claim 1, wherein the measuring step measures the compressor operation information including a stroke and a revolutions per minute (RPM).
 3. The method for controlling the swash plate compressor of claim 2, wherein the measuring step measures the stroke through a stroke sensor equipped in the swash plate compressor.
 4. The method for controlling the swash plate compressor of claim 2, wherein the measuring step measures the compressor operation information that further comprises a discharge pressure.
 5. The method for controlling the swash plate compressor of claim 4, wherein the measuring step measures the compressor operation information that further comprises a suction pressure.
 6. The method for controlling the swash plate compressor of claim 1, wherein the measuring step comprises: a cycle measuring step for measuring a reciprocating cycle of a piston of the swash plate compressor; a stroke calculating step for calculating a stroke of the swash plate compressor based on the reciprocating cycle of the piston measured in the cycle measuring step; and an RPM calculating step for calculating an RPM of the swash plate compressor based on the reciprocating cycle of the piston measured in the cycle measuring step.
 7. The method for controlling the swash plate compressor of claim 1, wherein the overload determining step determines that an overload occurred if the calculated torque value exceeds the torque set value.
 8. The method for controlling the swash plate compressor of claim 1, wherein the overload determining step determines that a load is normal if the calculated torque value is equal to or less than the torque set value, and wherein the method further comprises a refrigerant discharge amount adjusting step for adjusting the inclination angle of the swash plate based on a temperature of air flowed through an evaporator of an air-conditioner if the overload determining step determines that a load is normal.
 9. The method for controlling the swash plate compressor of claim 8, wherein the refrigerant discharge amount adjusting step comprises: an air temperature measuring step for measuring a temperature of air flowed through the evaporator; an air temperature comparing step for comparing the air temperature measured in the air temperature measuring step with an air temperature set value; and an inclination angle adjusting step for adjusting the inclination angle of the swash plate based on the comparison result of the air temperature comparing step.
 10. The method for controlling the swash plate compressor of claim 9, wherein the inclination angle adjusting step comprises: an inclination angle increasing step for increasing the inclination angle of the swash plate if the measured air temperature value exceeds the air temperature set value in the air temperature comparing step; and an inclination angle decreasing step for decreasing the inclination angle of the swash plate if the measured air temperature value is below the air temperature set value in the air temperature comparing step.
 11. The method for controlling the swash plate compressor of claim 1, further comprising: a transmitting step for transmitting the calculated torque value calculated in the torque calculating step to an engine control unit.
 12. A method for controlling a swash plate compressor, comprising: an air temperature measuring step for measuring a temperature of air flowed through an evaporator of an air-conditioner; a target stroke calculating step for calculating a target stroke based on a gap between the measured air temperature and an air temperature set value; a target ECV opening amount calculating step for calculating a target external control valve (ECV) opening amount based on the target stroke calculated in the target stroke calculating step; and an ECV opening amount adjusting step for adjusting an actual ECV opening amount to be a target ECV opening amount.
 13. The method for controlling the swash plate compressor of claim 12, further comprising: a stroke comparing step for comparing a measured stroke with a target stroke after the ECV opening amount adjusting step, wherein the ECV opening amount calculating step and the ECV opening amount adjusting step are retried if the measured stroke and the target stroke do not match in the stroke comparing step.
 14. A method for controlling a swash plate compressor, comprising: a measuring step for measuring a revolutions per minute (RPM) of a swash plate compressor; a comparing step for comparing the RPM measured in the measuring step with a calculated RPM; and a protecting step for stopping a clutch and generating an error alarm or for reducing an inclination angle of a swash plate to a minimum and generating an error alarm if the measured RPM and the calculated RPM do not match in the comparing step, and wherein the generation of an error alarm is characterized in lighting a warning lamp, or generating a diagnostic code.
 15. (canceled)
 16. A swash plate compressor, comprising: a housing having a crankcase, a cylinder bore, a suction chamber and a discharge chamber; a rotating shaft rotatably mounted on the housing; a swash plate rotating inside the crankcase and interworking with the rotating shaft; a piston interworking with the swash plate, reciprocating inside the cylinder bore and forming a compression chamber together with the cylinder bore; a measurement device measuring a reciprocating cycle of the piston; and a control device performing at least one among controlling a refrigerant discharge amount, controlling a torque, preventing belt slip and preventing compressor sticking according to the method of claim 1 based on the measured value of the measurement device, wherein the measurement device is a stroke sensor measuring a change in a magnetic field occurred by a groove formed in the piston when the piston reciprocates.
 17. (canceled)
 18. The swash plate compressor of claim 16, further comprising: a first pressure sensor disposed in the discharge chamber and measuring a discharge pressure.
 19. The swash plate compressor of claim 16, further comprising: a second pressure sensor disposed in the suction chamber and measuring a suction pressure.
 20. A method for controlling a swash plate compressor, comprising: a measuring step for measuring a compressor operation information of a swash plate compressor; a low refrigerant state determining step for determining whether the swash plate compressor is in a low refrigerant state or not; and an error alarm generating step for generating an error alarm if the swash plate compressor is in the low refrigerant state, wherein the generation of an error alarm is characterized in lighting a warning lamp, or generating a diagnostic code, wherein the measuring step measures the compressor operation information including a stroke, and wherein the low refrigerant state determining step is characterized in determining that the swash plate compressor is in the low refrigerant state if a gap between the current value of the stroke and a predetermined appropriate value of the stroke exceeds a first reference value.
 21. (canceled)
 22. The method for controlling a swash plate compressor of claim 20, wherein the measuring step measures the compressor operation information including a stroke and a discharge pressure; and a temperature of air flowed through an evaporator of an air-conditioner, and wherein the low refrigerant state determining step is characterized in: calculating a current refrigerant amount of the swash plate compressor by using the stroke, the discharge pressure and the air temperature; and determining that the swash plate compressor is in the low refrigerant state if a gap between a predetermined normal value of the refrigerant amount and the current refrigerant amount exceeds a second reference value. 